A Japanese graphic designer posted the milestone tweet at 4:44 Saturday afternoon, tweeting a friend who had just signed up for the service.
The man said that he felt like he had won the lottery and that at first he thought it was a joke. The 10 billionth tweet was posted just five months ago.
That means that there has been about 770 tweets every second for the last five months.
About 300,000 new users sign up for a Twitter account every day.